Heretofore, the emulsion has been applied by vertically slidable squeegees of a bucket type contacted at their front edges with the screen consisting of a screen material of silk, polyester, nylon or the like of a given mesh size and a frame surrounding the screen material. In this case, manual moving operation requires a particularly high skill for applying a film of a uniform thickness. In order to overcome the difficulty of the prior art, there have been proposed various types of mechanically moving squeegees, as disclosed in U.S. Pat. No. 4,363,289 (corres. to the Published European Patent Application No. 0026538). The U.S. patent relates to a method and an apparatus for applying an emulsion onto a screen printing, in which squeegees arranges at either side of the screen are advanced toward the screen face for contacting therewith, inclined for flowing the emulsion out of the squeegees at their front edges, and vertically moved relative to the screen. With this prior art, the emulsion flows down naturally from, the squeegees, so that the emulsion may be scraped by the front edge of the squeegee upon its upward movement for providing a uniform film thickness, whereas upon its downward movement (necessary for thick application) the emulsion may flow into the underside of the squeegee and is applied in different quantities thereby to provide a much irregular thickness. Upon application with the emulsion on both sides of the screen from its lower section, a certain distance between the screen face and the front edges of the squeegees is needed for giving a relatively thick emulsion film, because the contacted squeegees may scrape off the applied emulsion. Thus, the screen with a larger thickness of the emulsion on its printing side can not be produced. Further, the squeegees on both sides of the screen are symmetrically moved synchronously with each other by a single cylinder, so that one of the squeegees must be replaced by a rod or roller for application only on a single side of the screen, requiring a troublesome replacement and resulting in a very difficult switchover of the application from both sides to the single side of the screen or vice versa through continuous and automatic operation. Under printing with the screen, application of the more thick emulsion on the printing side than on the ink-applying side is essential for obtaining a beautiful print, which is difficult to be achieved by the prior art as described hereinabove. Further, since an arm for supporting and inclining the squeegees is supported to a slide which is slidably guided in a rail in order to move the squeegee forward and backward and since a piston for inclining the squeegee is swingable during forward and backward movement of the slide, correct control of the piston for inclining the squeegee is difficult after the end of the forward movement of the slide and setting of the slide into the rail is troublesome, resulting in a construction with complicated and troublesome controlling means.
Thus, an object of the invention is to solve the above problems of the prior art and to provide an apparatus for applying a more uniform thickness of an emulsion over the entire surface of a screen with its ink-applying side being thin while its printing side is thick for producing a beautiful print, in which one of squeegees arranged on one side of the screen is used for applying the emulsion while the other is used for scraping and recovering the emulsion, in which each of the squeegees is movable independently and only the applying squeegee may be inclined, and in which the emulsion is applied only during upward movement of the applying squeegee while the uniform application of the emulsion through the screen mesh and its recovery may be effected.